xref: /openbmc/linux/arch/ia64/kernel/smpboot.c (revision 643d1f7f)
1 /*
2  * SMP boot-related support
3  *
4  * Copyright (C) 1998-2003, 2005 Hewlett-Packard Co
5  *	David Mosberger-Tang <davidm@hpl.hp.com>
6  * Copyright (C) 2001, 2004-2005 Intel Corp
7  * 	Rohit Seth <rohit.seth@intel.com>
8  * 	Suresh Siddha <suresh.b.siddha@intel.com>
9  * 	Gordon Jin <gordon.jin@intel.com>
10  *	Ashok Raj  <ashok.raj@intel.com>
11  *
12  * 01/05/16 Rohit Seth <rohit.seth@intel.com>	Moved SMP booting functions from smp.c to here.
13  * 01/04/27 David Mosberger <davidm@hpl.hp.com>	Added ITC synching code.
14  * 02/07/31 David Mosberger <davidm@hpl.hp.com>	Switch over to hotplug-CPU boot-sequence.
15  *						smp_boot_cpus()/smp_commence() is replaced by
16  *						smp_prepare_cpus()/__cpu_up()/smp_cpus_done().
17  * 04/06/21 Ashok Raj		<ashok.raj@intel.com> Added CPU Hotplug Support
18  * 04/12/26 Jin Gordon <gordon.jin@intel.com>
19  * 04/12/26 Rohit Seth <rohit.seth@intel.com>
20  *						Add multi-threading and multi-core detection
21  * 05/01/30 Suresh Siddha <suresh.b.siddha@intel.com>
22  *						Setup cpu_sibling_map and cpu_core_map
23  */
24 
25 #include <linux/module.h>
26 #include <linux/acpi.h>
27 #include <linux/bootmem.h>
28 #include <linux/cpu.h>
29 #include <linux/delay.h>
30 #include <linux/init.h>
31 #include <linux/interrupt.h>
32 #include <linux/irq.h>
33 #include <linux/kernel.h>
34 #include <linux/kernel_stat.h>
35 #include <linux/mm.h>
36 #include <linux/notifier.h>
37 #include <linux/smp.h>
38 #include <linux/spinlock.h>
39 #include <linux/efi.h>
40 #include <linux/percpu.h>
41 #include <linux/bitops.h>
42 
43 #include <asm/atomic.h>
44 #include <asm/cache.h>
45 #include <asm/current.h>
46 #include <asm/delay.h>
47 #include <asm/ia32.h>
48 #include <asm/io.h>
49 #include <asm/irq.h>
50 #include <asm/machvec.h>
51 #include <asm/mca.h>
52 #include <asm/page.h>
53 #include <asm/pgalloc.h>
54 #include <asm/pgtable.h>
55 #include <asm/processor.h>
56 #include <asm/ptrace.h>
57 #include <asm/sal.h>
58 #include <asm/system.h>
59 #include <asm/tlbflush.h>
60 #include <asm/unistd.h>
61 #include <asm/sn/arch.h>
62 
63 #define SMP_DEBUG 0
64 
65 #if SMP_DEBUG
66 #define Dprintk(x...)  printk(x)
67 #else
68 #define Dprintk(x...)
69 #endif
70 
71 #ifdef CONFIG_HOTPLUG_CPU
72 #ifdef CONFIG_PERMIT_BSP_REMOVE
73 #define bsp_remove_ok	1
74 #else
75 #define bsp_remove_ok	0
76 #endif
77 
78 /*
79  * Store all idle threads, this can be reused instead of creating
80  * a new thread. Also avoids complicated thread destroy functionality
81  * for idle threads.
82  */
83 struct task_struct *idle_thread_array[NR_CPUS];
84 
85 /*
86  * Global array allocated for NR_CPUS at boot time
87  */
88 struct sal_to_os_boot sal_boot_rendez_state[NR_CPUS];
89 
90 /*
91  * start_ap in head.S uses this to store current booting cpu
92  * info.
93  */
94 struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
95 
96 #define set_brendez_area(x) (sal_state_for_booting_cpu = &sal_boot_rendez_state[(x)]);
97 
98 #define get_idle_for_cpu(x)		(idle_thread_array[(x)])
99 #define set_idle_for_cpu(x,p)	(idle_thread_array[(x)] = (p))
100 
101 #else
102 
103 #define get_idle_for_cpu(x)		(NULL)
104 #define set_idle_for_cpu(x,p)
105 #define set_brendez_area(x)
106 #endif
107 
108 
109 /*
110  * ITC synchronization related stuff:
111  */
112 #define MASTER	(0)
113 #define SLAVE	(SMP_CACHE_BYTES/8)
114 
115 #define NUM_ROUNDS	64	/* magic value */
116 #define NUM_ITERS	5	/* likewise */
117 
118 static DEFINE_SPINLOCK(itc_sync_lock);
119 static volatile unsigned long go[SLAVE + 1];
120 
121 #define DEBUG_ITC_SYNC	0
122 
123 extern void __devinit calibrate_delay (void);
124 extern void start_ap (void);
125 extern unsigned long ia64_iobase;
126 
127 struct task_struct *task_for_booting_cpu;
128 
129 /*
130  * State for each CPU
131  */
132 DEFINE_PER_CPU(int, cpu_state);
133 
134 /* Bitmasks of currently online, and possible CPUs */
135 cpumask_t cpu_online_map;
136 EXPORT_SYMBOL(cpu_online_map);
137 cpumask_t cpu_possible_map = CPU_MASK_NONE;
138 EXPORT_SYMBOL(cpu_possible_map);
139 
140 cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
141 DEFINE_PER_CPU_SHARED_ALIGNED(cpumask_t, cpu_sibling_map);
142 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
143 
144 int smp_num_siblings = 1;
145 
146 /* which logical CPU number maps to which CPU (physical APIC ID) */
147 volatile int ia64_cpu_to_sapicid[NR_CPUS];
148 EXPORT_SYMBOL(ia64_cpu_to_sapicid);
149 
150 static volatile cpumask_t cpu_callin_map;
151 
152 struct smp_boot_data smp_boot_data __initdata;
153 
154 unsigned long ap_wakeup_vector = -1; /* External Int use to wakeup APs */
155 
156 char __initdata no_int_routing;
157 
158 unsigned char smp_int_redirect; /* are INT and IPI redirectable by the chipset? */
159 
160 #ifdef CONFIG_FORCE_CPEI_RETARGET
161 #define CPEI_OVERRIDE_DEFAULT	(1)
162 #else
163 #define CPEI_OVERRIDE_DEFAULT	(0)
164 #endif
165 
166 unsigned int force_cpei_retarget = CPEI_OVERRIDE_DEFAULT;
167 
168 static int __init
169 cmdl_force_cpei(char *str)
170 {
171 	int value=0;
172 
173 	get_option (&str, &value);
174 	force_cpei_retarget = value;
175 
176 	return 1;
177 }
178 
179 __setup("force_cpei=", cmdl_force_cpei);
180 
181 static int __init
182 nointroute (char *str)
183 {
184 	no_int_routing = 1;
185 	printk ("no_int_routing on\n");
186 	return 1;
187 }
188 
189 __setup("nointroute", nointroute);
190 
191 static void fix_b0_for_bsp(void)
192 {
193 #ifdef CONFIG_HOTPLUG_CPU
194 	int cpuid;
195 	static int fix_bsp_b0 = 1;
196 
197 	cpuid = smp_processor_id();
198 
199 	/*
200 	 * Cache the b0 value on the first AP that comes up
201 	 */
202 	if (!(fix_bsp_b0 && cpuid))
203 		return;
204 
205 	sal_boot_rendez_state[0].br[0] = sal_boot_rendez_state[cpuid].br[0];
206 	printk ("Fixed BSP b0 value from CPU %d\n", cpuid);
207 
208 	fix_bsp_b0 = 0;
209 #endif
210 }
211 
212 void
213 sync_master (void *arg)
214 {
215 	unsigned long flags, i;
216 
217 	go[MASTER] = 0;
218 
219 	local_irq_save(flags);
220 	{
221 		for (i = 0; i < NUM_ROUNDS*NUM_ITERS; ++i) {
222 			while (!go[MASTER])
223 				cpu_relax();
224 			go[MASTER] = 0;
225 			go[SLAVE] = ia64_get_itc();
226 		}
227 	}
228 	local_irq_restore(flags);
229 }
230 
231 /*
232  * Return the number of cycles by which our itc differs from the itc on the master
233  * (time-keeper) CPU.  A positive number indicates our itc is ahead of the master,
234  * negative that it is behind.
235  */
236 static inline long
237 get_delta (long *rt, long *master)
238 {
239 	unsigned long best_t0 = 0, best_t1 = ~0UL, best_tm = 0;
240 	unsigned long tcenter, t0, t1, tm;
241 	long i;
242 
243 	for (i = 0; i < NUM_ITERS; ++i) {
244 		t0 = ia64_get_itc();
245 		go[MASTER] = 1;
246 		while (!(tm = go[SLAVE]))
247 			cpu_relax();
248 		go[SLAVE] = 0;
249 		t1 = ia64_get_itc();
250 
251 		if (t1 - t0 < best_t1 - best_t0)
252 			best_t0 = t0, best_t1 = t1, best_tm = tm;
253 	}
254 
255 	*rt = best_t1 - best_t0;
256 	*master = best_tm - best_t0;
257 
258 	/* average best_t0 and best_t1 without overflow: */
259 	tcenter = (best_t0/2 + best_t1/2);
260 	if (best_t0 % 2 + best_t1 % 2 == 2)
261 		++tcenter;
262 	return tcenter - best_tm;
263 }
264 
265 /*
266  * Synchronize ar.itc of the current (slave) CPU with the ar.itc of the MASTER CPU
267  * (normally the time-keeper CPU).  We use a closed loop to eliminate the possibility of
268  * unaccounted-for errors (such as getting a machine check in the middle of a calibration
269  * step).  The basic idea is for the slave to ask the master what itc value it has and to
270  * read its own itc before and after the master responds.  Each iteration gives us three
271  * timestamps:
272  *
273  *	slave		master
274  *
275  *	t0 ---\
276  *             ---\
277  *		   --->
278  *			tm
279  *		   /---
280  *	       /---
281  *	t1 <---
282  *
283  *
284  * The goal is to adjust the slave's ar.itc such that tm falls exactly half-way between t0
285  * and t1.  If we achieve this, the clocks are synchronized provided the interconnect
286  * between the slave and the master is symmetric.  Even if the interconnect were
287  * asymmetric, we would still know that the synchronization error is smaller than the
288  * roundtrip latency (t0 - t1).
289  *
290  * When the interconnect is quiet and symmetric, this lets us synchronize the itc to
291  * within one or two cycles.  However, we can only *guarantee* that the synchronization is
292  * accurate to within a round-trip time, which is typically in the range of several
293  * hundred cycles (e.g., ~500 cycles).  In practice, this means that the itc's are usually
294  * almost perfectly synchronized, but we shouldn't assume that the accuracy is much better
295  * than half a micro second or so.
296  */
297 void
298 ia64_sync_itc (unsigned int master)
299 {
300 	long i, delta, adj, adjust_latency = 0, done = 0;
301 	unsigned long flags, rt, master_time_stamp, bound;
302 #if DEBUG_ITC_SYNC
303 	struct {
304 		long rt;	/* roundtrip time */
305 		long master;	/* master's timestamp */
306 		long diff;	/* difference between midpoint and master's timestamp */
307 		long lat;	/* estimate of itc adjustment latency */
308 	} t[NUM_ROUNDS];
309 #endif
310 
311 	/*
312 	 * Make sure local timer ticks are disabled while we sync.  If
313 	 * they were enabled, we'd have to worry about nasty issues
314 	 * like setting the ITC ahead of (or a long time before) the
315 	 * next scheduled tick.
316 	 */
317 	BUG_ON((ia64_get_itv() & (1 << 16)) == 0);
318 
319 	go[MASTER] = 1;
320 
321 	if (smp_call_function_single(master, sync_master, NULL, 1, 0) < 0) {
322 		printk(KERN_ERR "sync_itc: failed to get attention of CPU %u!\n", master);
323 		return;
324 	}
325 
326 	while (go[MASTER])
327 		cpu_relax();	/* wait for master to be ready */
328 
329 	spin_lock_irqsave(&itc_sync_lock, flags);
330 	{
331 		for (i = 0; i < NUM_ROUNDS; ++i) {
332 			delta = get_delta(&rt, &master_time_stamp);
333 			if (delta == 0) {
334 				done = 1;	/* let's lock on to this... */
335 				bound = rt;
336 			}
337 
338 			if (!done) {
339 				if (i > 0) {
340 					adjust_latency += -delta;
341 					adj = -delta + adjust_latency/4;
342 				} else
343 					adj = -delta;
344 
345 				ia64_set_itc(ia64_get_itc() + adj);
346 			}
347 #if DEBUG_ITC_SYNC
348 			t[i].rt = rt;
349 			t[i].master = master_time_stamp;
350 			t[i].diff = delta;
351 			t[i].lat = adjust_latency/4;
352 #endif
353 		}
354 	}
355 	spin_unlock_irqrestore(&itc_sync_lock, flags);
356 
357 #if DEBUG_ITC_SYNC
358 	for (i = 0; i < NUM_ROUNDS; ++i)
359 		printk("rt=%5ld master=%5ld diff=%5ld adjlat=%5ld\n",
360 		       t[i].rt, t[i].master, t[i].diff, t[i].lat);
361 #endif
362 
363 	printk(KERN_INFO "CPU %d: synchronized ITC with CPU %u (last diff %ld cycles, "
364 	       "maxerr %lu cycles)\n", smp_processor_id(), master, delta, rt);
365 }
366 
367 /*
368  * Ideally sets up per-cpu profiling hooks.  Doesn't do much now...
369  */
370 static inline void __devinit
371 smp_setup_percpu_timer (void)
372 {
373 }
374 
375 static void __cpuinit
376 smp_callin (void)
377 {
378 	int cpuid, phys_id, itc_master;
379 	struct cpuinfo_ia64 *last_cpuinfo, *this_cpuinfo;
380 	extern void ia64_init_itm(void);
381 	extern volatile int time_keeper_id;
382 
383 #ifdef CONFIG_PERFMON
384 	extern void pfm_init_percpu(void);
385 #endif
386 
387 	cpuid = smp_processor_id();
388 	phys_id = hard_smp_processor_id();
389 	itc_master = time_keeper_id;
390 
391 	if (cpu_online(cpuid)) {
392 		printk(KERN_ERR "huh, phys CPU#0x%x, CPU#0x%x already present??\n",
393 		       phys_id, cpuid);
394 		BUG();
395 	}
396 
397 	fix_b0_for_bsp();
398 
399 	lock_ipi_calllock();
400 	spin_lock(&vector_lock);
401 	/* Setup the per cpu irq handling data structures */
402 	__setup_vector_irq(cpuid);
403 	cpu_set(cpuid, cpu_online_map);
404 	unlock_ipi_calllock();
405 	per_cpu(cpu_state, cpuid) = CPU_ONLINE;
406 	spin_unlock(&vector_lock);
407 
408 	smp_setup_percpu_timer();
409 
410 	ia64_mca_cmc_vector_setup();	/* Setup vector on AP */
411 
412 #ifdef CONFIG_PERFMON
413 	pfm_init_percpu();
414 #endif
415 
416 	local_irq_enable();
417 
418 	if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
419 		/*
420 		 * Synchronize the ITC with the BP.  Need to do this after irqs are
421 		 * enabled because ia64_sync_itc() calls smp_call_function_single(), which
422 		 * calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
423 		 * local_bh_enable(), which bugs out if irqs are not enabled...
424 		 */
425 		Dprintk("Going to syncup ITC with ITC Master.\n");
426 		ia64_sync_itc(itc_master);
427 	}
428 
429 	/*
430 	 * Get our bogomips.
431 	 */
432 	ia64_init_itm();
433 
434 	/*
435 	 * Delay calibration can be skipped if new processor is identical to the
436 	 * previous processor.
437 	 */
438 	last_cpuinfo = cpu_data(cpuid - 1);
439 	this_cpuinfo = local_cpu_data;
440 	if (last_cpuinfo->itc_freq != this_cpuinfo->itc_freq ||
441 	    last_cpuinfo->proc_freq != this_cpuinfo->proc_freq ||
442 	    last_cpuinfo->features != this_cpuinfo->features ||
443 	    last_cpuinfo->revision != this_cpuinfo->revision ||
444 	    last_cpuinfo->family != this_cpuinfo->family ||
445 	    last_cpuinfo->archrev != this_cpuinfo->archrev ||
446 	    last_cpuinfo->model != this_cpuinfo->model)
447 		calibrate_delay();
448 	local_cpu_data->loops_per_jiffy = loops_per_jiffy;
449 
450 #ifdef CONFIG_IA32_SUPPORT
451 	ia32_gdt_init();
452 #endif
453 
454 	/*
455 	 * Allow the master to continue.
456 	 */
457 	cpu_set(cpuid, cpu_callin_map);
458 	Dprintk("Stack on CPU %d at about %p\n",cpuid, &cpuid);
459 }
460 
461 
462 /*
463  * Activate a secondary processor.  head.S calls this.
464  */
465 int __cpuinit
466 start_secondary (void *unused)
467 {
468 	/* Early console may use I/O ports */
469 	ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));
470 	Dprintk("start_secondary: starting CPU 0x%x\n", hard_smp_processor_id());
471 	efi_map_pal_code();
472 	cpu_init();
473 	preempt_disable();
474 	smp_callin();
475 
476 	cpu_idle();
477 	return 0;
478 }
479 
480 struct pt_regs * __devinit idle_regs(struct pt_regs *regs)
481 {
482 	return NULL;
483 }
484 
485 struct create_idle {
486 	struct work_struct work;
487 	struct task_struct *idle;
488 	struct completion done;
489 	int cpu;
490 };
491 
492 void __cpuinit
493 do_fork_idle(struct work_struct *work)
494 {
495 	struct create_idle *c_idle =
496 		container_of(work, struct create_idle, work);
497 
498 	c_idle->idle = fork_idle(c_idle->cpu);
499 	complete(&c_idle->done);
500 }
501 
502 static int __cpuinit
503 do_boot_cpu (int sapicid, int cpu)
504 {
505 	int timeout;
506 	struct create_idle c_idle = {
507 		.work = __WORK_INITIALIZER(c_idle.work, do_fork_idle),
508 		.cpu	= cpu,
509 		.done	= COMPLETION_INITIALIZER(c_idle.done),
510 	};
511 
512  	c_idle.idle = get_idle_for_cpu(cpu);
513  	if (c_idle.idle) {
514 		init_idle(c_idle.idle, cpu);
515  		goto do_rest;
516 	}
517 
518 	/*
519 	 * We can't use kernel_thread since we must avoid to reschedule the child.
520 	 */
521 	if (!keventd_up() || current_is_keventd())
522 		c_idle.work.func(&c_idle.work);
523 	else {
524 		schedule_work(&c_idle.work);
525 		wait_for_completion(&c_idle.done);
526 	}
527 
528 	if (IS_ERR(c_idle.idle))
529 		panic("failed fork for CPU %d", cpu);
530 
531 	set_idle_for_cpu(cpu, c_idle.idle);
532 
533 do_rest:
534 	task_for_booting_cpu = c_idle.idle;
535 
536 	Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);
537 
538 	set_brendez_area(cpu);
539 	platform_send_ipi(cpu, ap_wakeup_vector, IA64_IPI_DM_INT, 0);
540 
541 	/*
542 	 * Wait 10s total for the AP to start
543 	 */
544 	Dprintk("Waiting on callin_map ...");
545 	for (timeout = 0; timeout < 100000; timeout++) {
546 		if (cpu_isset(cpu, cpu_callin_map))
547 			break;  /* It has booted */
548 		udelay(100);
549 	}
550 	Dprintk("\n");
551 
552 	if (!cpu_isset(cpu, cpu_callin_map)) {
553 		printk(KERN_ERR "Processor 0x%x/0x%x is stuck.\n", cpu, sapicid);
554 		ia64_cpu_to_sapicid[cpu] = -1;
555 		cpu_clear(cpu, cpu_online_map);  /* was set in smp_callin() */
556 		return -EINVAL;
557 	}
558 	return 0;
559 }
560 
561 static int __init
562 decay (char *str)
563 {
564 	int ticks;
565 	get_option (&str, &ticks);
566 	return 1;
567 }
568 
569 __setup("decay=", decay);
570 
571 /*
572  * Initialize the logical CPU number to SAPICID mapping
573  */
574 void __init
575 smp_build_cpu_map (void)
576 {
577 	int sapicid, cpu, i;
578 	int boot_cpu_id = hard_smp_processor_id();
579 
580 	for (cpu = 0; cpu < NR_CPUS; cpu++) {
581 		ia64_cpu_to_sapicid[cpu] = -1;
582 	}
583 
584 	ia64_cpu_to_sapicid[0] = boot_cpu_id;
585 	cpus_clear(cpu_present_map);
586 	cpu_set(0, cpu_present_map);
587 	cpu_set(0, cpu_possible_map);
588 	for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) {
589 		sapicid = smp_boot_data.cpu_phys_id[i];
590 		if (sapicid == boot_cpu_id)
591 			continue;
592 		cpu_set(cpu, cpu_present_map);
593 		cpu_set(cpu, cpu_possible_map);
594 		ia64_cpu_to_sapicid[cpu] = sapicid;
595 		cpu++;
596 	}
597 }
598 
599 /*
600  * Cycle through the APs sending Wakeup IPIs to boot each.
601  */
602 void __init
603 smp_prepare_cpus (unsigned int max_cpus)
604 {
605 	int boot_cpu_id = hard_smp_processor_id();
606 
607 	/*
608 	 * Initialize the per-CPU profiling counter/multiplier
609 	 */
610 
611 	smp_setup_percpu_timer();
612 
613 	/*
614 	 * We have the boot CPU online for sure.
615 	 */
616 	cpu_set(0, cpu_online_map);
617 	cpu_set(0, cpu_callin_map);
618 
619 	local_cpu_data->loops_per_jiffy = loops_per_jiffy;
620 	ia64_cpu_to_sapicid[0] = boot_cpu_id;
621 
622 	printk(KERN_INFO "Boot processor id 0x%x/0x%x\n", 0, boot_cpu_id);
623 
624 	current_thread_info()->cpu = 0;
625 
626 	/*
627 	 * If SMP should be disabled, then really disable it!
628 	 */
629 	if (!max_cpus) {
630 		printk(KERN_INFO "SMP mode deactivated.\n");
631 		cpus_clear(cpu_online_map);
632 		cpus_clear(cpu_present_map);
633 		cpus_clear(cpu_possible_map);
634 		cpu_set(0, cpu_online_map);
635 		cpu_set(0, cpu_present_map);
636 		cpu_set(0, cpu_possible_map);
637 		return;
638 	}
639 }
640 
641 void __devinit smp_prepare_boot_cpu(void)
642 {
643 	cpu_set(smp_processor_id(), cpu_online_map);
644 	cpu_set(smp_processor_id(), cpu_callin_map);
645 	per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
646 }
647 
648 #ifdef CONFIG_HOTPLUG_CPU
649 static inline void
650 clear_cpu_sibling_map(int cpu)
651 {
652 	int i;
653 
654 	for_each_cpu_mask(i, per_cpu(cpu_sibling_map, cpu))
655 		cpu_clear(cpu, per_cpu(cpu_sibling_map, i));
656 	for_each_cpu_mask(i, cpu_core_map[cpu])
657 		cpu_clear(cpu, cpu_core_map[i]);
658 
659 	per_cpu(cpu_sibling_map, cpu) = cpu_core_map[cpu] = CPU_MASK_NONE;
660 }
661 
662 static void
663 remove_siblinginfo(int cpu)
664 {
665 	int last = 0;
666 
667 	if (cpu_data(cpu)->threads_per_core == 1 &&
668 	    cpu_data(cpu)->cores_per_socket == 1) {
669 		cpu_clear(cpu, cpu_core_map[cpu]);
670 		cpu_clear(cpu, per_cpu(cpu_sibling_map, cpu));
671 		return;
672 	}
673 
674 	last = (cpus_weight(cpu_core_map[cpu]) == 1 ? 1 : 0);
675 
676 	/* remove it from all sibling map's */
677 	clear_cpu_sibling_map(cpu);
678 }
679 
680 extern void fixup_irqs(void);
681 
682 int migrate_platform_irqs(unsigned int cpu)
683 {
684 	int new_cpei_cpu;
685 	irq_desc_t *desc = NULL;
686 	cpumask_t 	mask;
687 	int 		retval = 0;
688 
689 	/*
690 	 * dont permit CPEI target to removed.
691 	 */
692 	if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
693 		printk ("CPU (%d) is CPEI Target\n", cpu);
694 		if (can_cpei_retarget()) {
695 			/*
696 			 * Now re-target the CPEI to a different processor
697 			 */
698 			new_cpei_cpu = any_online_cpu(cpu_online_map);
699 			mask = cpumask_of_cpu(new_cpei_cpu);
700 			set_cpei_target_cpu(new_cpei_cpu);
701 			desc = irq_desc + ia64_cpe_irq;
702 			/*
703 			 * Switch for now, immediately, we need to do fake intr
704 			 * as other interrupts, but need to study CPEI behaviour with
705 			 * polling before making changes.
706 			 */
707 			if (desc) {
708 				desc->chip->disable(ia64_cpe_irq);
709 				desc->chip->set_affinity(ia64_cpe_irq, mask);
710 				desc->chip->enable(ia64_cpe_irq);
711 				printk ("Re-targetting CPEI to cpu %d\n", new_cpei_cpu);
712 			}
713 		}
714 		if (!desc) {
715 			printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
716 			retval = -EBUSY;
717 		}
718 	}
719 	return retval;
720 }
721 
722 /* must be called with cpucontrol mutex held */
723 int __cpu_disable(void)
724 {
725 	int cpu = smp_processor_id();
726 
727 	/*
728 	 * dont permit boot processor for now
729 	 */
730 	if (cpu == 0 && !bsp_remove_ok) {
731 		printk ("Your platform does not support removal of BSP\n");
732 		return (-EBUSY);
733 	}
734 
735 	if (ia64_platform_is("sn2")) {
736 		if (!sn_cpu_disable_allowed(cpu))
737 			return -EBUSY;
738 	}
739 
740 	cpu_clear(cpu, cpu_online_map);
741 
742 	if (migrate_platform_irqs(cpu)) {
743 		cpu_set(cpu, cpu_online_map);
744 		return (-EBUSY);
745 	}
746 
747 	remove_siblinginfo(cpu);
748 	cpu_clear(cpu, cpu_online_map);
749 	fixup_irqs();
750 	local_flush_tlb_all();
751 	cpu_clear(cpu, cpu_callin_map);
752 	return 0;
753 }
754 
755 void __cpu_die(unsigned int cpu)
756 {
757 	unsigned int i;
758 
759 	for (i = 0; i < 100; i++) {
760 		/* They ack this in play_dead by setting CPU_DEAD */
761 		if (per_cpu(cpu_state, cpu) == CPU_DEAD)
762 		{
763 			printk ("CPU %d is now offline\n", cpu);
764 			return;
765 		}
766 		msleep(100);
767 	}
768  	printk(KERN_ERR "CPU %u didn't die...\n", cpu);
769 }
770 #else /* !CONFIG_HOTPLUG_CPU */
771 int __cpu_disable(void)
772 {
773 	return -ENOSYS;
774 }
775 
776 void __cpu_die(unsigned int cpu)
777 {
778 	/* We said "no" in __cpu_disable */
779 	BUG();
780 }
781 #endif /* CONFIG_HOTPLUG_CPU */
782 
783 void
784 smp_cpus_done (unsigned int dummy)
785 {
786 	int cpu;
787 	unsigned long bogosum = 0;
788 
789 	/*
790 	 * Allow the user to impress friends.
791 	 */
792 
793 	for_each_online_cpu(cpu) {
794 		bogosum += cpu_data(cpu)->loops_per_jiffy;
795 	}
796 
797 	printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
798 	       (int)num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100);
799 }
800 
801 static inline void __devinit
802 set_cpu_sibling_map(int cpu)
803 {
804 	int i;
805 
806 	for_each_online_cpu(i) {
807 		if ((cpu_data(cpu)->socket_id == cpu_data(i)->socket_id)) {
808 			cpu_set(i, cpu_core_map[cpu]);
809 			cpu_set(cpu, cpu_core_map[i]);
810 			if (cpu_data(cpu)->core_id == cpu_data(i)->core_id) {
811 				cpu_set(i, per_cpu(cpu_sibling_map, cpu));
812 				cpu_set(cpu, per_cpu(cpu_sibling_map, i));
813 			}
814 		}
815 	}
816 }
817 
818 int __cpuinit
819 __cpu_up (unsigned int cpu)
820 {
821 	int ret;
822 	int sapicid;
823 
824 	sapicid = ia64_cpu_to_sapicid[cpu];
825 	if (sapicid == -1)
826 		return -EINVAL;
827 
828 	/*
829 	 * Already booted cpu? not valid anymore since we dont
830 	 * do idle loop tightspin anymore.
831 	 */
832 	if (cpu_isset(cpu, cpu_callin_map))
833 		return -EINVAL;
834 
835 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
836 	/* Processor goes to start_secondary(), sets online flag */
837 	ret = do_boot_cpu(sapicid, cpu);
838 	if (ret < 0)
839 		return ret;
840 
841 	if (cpu_data(cpu)->threads_per_core == 1 &&
842 	    cpu_data(cpu)->cores_per_socket == 1) {
843 		cpu_set(cpu, per_cpu(cpu_sibling_map, cpu));
844 		cpu_set(cpu, cpu_core_map[cpu]);
845 		return 0;
846 	}
847 
848 	set_cpu_sibling_map(cpu);
849 
850 	return 0;
851 }
852 
853 /*
854  * Assume that CPUs have been discovered by some platform-dependent interface.  For
855  * SoftSDV/Lion, that would be ACPI.
856  *
857  * Setup of the IPI irq handler is done in irq.c:init_IRQ_SMP().
858  */
859 void __init
860 init_smp_config(void)
861 {
862 	struct fptr {
863 		unsigned long fp;
864 		unsigned long gp;
865 	} *ap_startup;
866 	long sal_ret;
867 
868 	/* Tell SAL where to drop the APs.  */
869 	ap_startup = (struct fptr *) start_ap;
870 	sal_ret = ia64_sal_set_vectors(SAL_VECTOR_OS_BOOT_RENDEZ,
871 				       ia64_tpa(ap_startup->fp), ia64_tpa(ap_startup->gp), 0, 0, 0, 0);
872 	if (sal_ret < 0)
873 		printk(KERN_ERR "SMP: Can't set SAL AP Boot Rendezvous: %s\n",
874 		       ia64_sal_strerror(sal_ret));
875 }
876 
877 /*
878  * identify_siblings(cpu) gets called from identify_cpu. This populates the
879  * information related to logical execution units in per_cpu_data structure.
880  */
881 void __devinit
882 identify_siblings(struct cpuinfo_ia64 *c)
883 {
884 	s64 status;
885 	u16 pltid;
886 	pal_logical_to_physical_t info;
887 
888 	if ((status = ia64_pal_logical_to_phys(-1, &info)) != PAL_STATUS_SUCCESS) {
889 		if (status != PAL_STATUS_UNIMPLEMENTED) {
890 			printk(KERN_ERR
891 				"ia64_pal_logical_to_phys failed with %ld\n",
892 				status);
893 			return;
894 		}
895 
896 		info.overview_ppid = 0;
897 		info.overview_cpp  = 1;
898 		info.overview_tpc  = 1;
899 	}
900 	if ((status = ia64_sal_physical_id_info(&pltid)) != PAL_STATUS_SUCCESS) {
901 		printk(KERN_ERR "ia64_sal_pltid failed with %ld\n", status);
902 		return;
903 	}
904 
905 	c->socket_id =  (pltid << 8) | info.overview_ppid;
906 
907 	if (info.overview_cpp == 1 && info.overview_tpc == 1)
908 		return;
909 
910 	c->cores_per_socket = info.overview_cpp;
911 	c->threads_per_core = info.overview_tpc;
912 	c->num_log = info.overview_num_log;
913 
914 	c->core_id = info.log1_cid;
915 	c->thread_id = info.log1_tid;
916 }
917 
918 /*
919  * returns non zero, if multi-threading is enabled
920  * on at least one physical package. Due to hotplug cpu
921  * and (maxcpus=), all threads may not necessarily be enabled
922  * even though the processor supports multi-threading.
923  */
924 int is_multithreading_enabled(void)
925 {
926 	int i, j;
927 
928 	for_each_present_cpu(i) {
929 		for_each_present_cpu(j) {
930 			if (j == i)
931 				continue;
932 			if ((cpu_data(j)->socket_id == cpu_data(i)->socket_id)) {
933 				if (cpu_data(j)->core_id == cpu_data(i)->core_id)
934 					return 1;
935 			}
936 		}
937 	}
938 	return 0;
939 }
940 EXPORT_SYMBOL_GPL(is_multithreading_enabled);
941